用于实现互联系统仿真的电源模块大信号模型

Large-Signal Model of Power Supply Modules for Implementing Inter-Connected System Simulations

提出一种新的针对双环控制结构电源模块(含连续导通模式功率因数校正器模块和电流模式控制DC-DC模块)的大信号建模方法,目的在于克服互联系统单纯采用开关模型实现仿真时遇到的困难.该方法利用双环控制系统中内环响应速度快、外环控制器所给出的指令信号变化缓慢这一特点,将内环闭环传输特性用比例环节等效实现;利用平均意义下的瞬时功率平衡关系,用模拟主电路功率流动规律的代数运算单元替代含有复杂开关过程的主电路.以上方法简化了控制电路,避开了耗时的开关过程,最终使双环控制的开关系统转化成为单环控制的以连续平均量为变量的非线性系统.仿真结果表明,在保证准确反映电源模块端口特性的同时,采用本文模型仿真,较之采用开关模型,仿真速度显著加快.

Pursuing rapid simulation speed and requiring reflection of more circuit details are always contradictory in computer simulations, especially for those of complex circuits such as a distributed power system. Simplified models of power supply modules are expected to establish a balance between above two requirements in implementing inter-connected system simulations. After discussing the difficulties in attempting to simulate inter-connected systems with switching models, the features of double-loop controlled power supply modules are investigated, in which cover a range of modules including continuous conduction mode （CCM） power factor correction （PFC） rectifiers and current mode controlled dc-dc converters. A new modeling approach is proposed, which the main idea is to simplify the double-loop controlling structure to a single-loop one by equating the inner current loop with a proportional gain block and furthermore treating the power stage as a power conservation unit that only externally represents the averaged voltage-ampere relations at both input and output ports through arithmetic calculation. A double-loop controlled switching system is transformed to a single-loop controlled non-linear system with continuous averaged variables in the proposed approach. The validity of the proposed model is verified by comparing the simulation speed and waveforms obtained respectively from switching models and the proposed model.